231816 has 32 divisors (see below), whose sum is σ = 624960. Its totient is φ = 71232.

The previous prime is 231809. The next prime is 231821. The reversal of 231816 is 618132.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 231792 and 231801.

It is an unprimeable number.

231816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60 + ... + 683.

It is an arithmetic number, because the mean of its divisors is an integer number (19530).

2²³¹⁸¹⁶ is an apocalyptic number.

231816 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (312480).

231816 is an abundant number, since it is smaller than the sum of its proper divisors (393144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231816 is a wasteful number, since it uses less digits than its factorization.

231816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765 (or 761 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 231816 is about 481.4727406614. The cubic root of 231816 is about 61.4300877835.

Adding to 231816 its reverse (618132), we get a palindrome (849948).

The spelling of 231816 in words is "two hundred thirty-one thousand, eight hundred sixteen".